Good day to all, who`s going to read this guide.
Okay, a few words about why I choose this champ. Malzahar is amazing mid lane champion and it`s really easy to farm gold, it has a very powerful spells which killing everything :
"Q" -> Call of the Void = 3 sec of SILENCE!
"W" -> Null Zone = perfect with your "R"+"E" agaist tanks.
"E" -> Malefic Visions = precisely because of this spell you are farming a lot of gold.
"R" -> Nether Grasp = if you can make combo: "E"->"W"->"R" everything dies.

(Sorry for my mistakes, I`m from Ukraine & I don`t know English as well as you.)

Mark of Magic Penetration + Greater Quintessence of Ability Power - it will gives you ability power at first level + ignor magic resist.
Seal of Armor - well, I even don`t know when protaction is useless...think about it.
Glyph of Cooldown Reduction - it`ll give you 7.5% cdr + 5% from masteries Sorcery = 12.5% cdr. well this combination is working always.

Athene's Unholy Grail - it`s good for you if ap carry is fed and you need mr(magic resistence); As for cdr (cooldown reduction) item it`s bad,becouse actualy Malzahar needs above 20-25% cdr.
Void Staff - take this if enemy team has a lot of mr and you feel, that Devastating Strikes becomes weak.
Rylai's Crystal Scepter - if you want and like to chase enemy + you like a lot hp take this.
Using your Malefic Visions + passive from Rylai's Crystal Scepter opponent can`t run from you.
Deathfire Grasp - by using this you become one shot beast.
Zhonya's Hourglass - very important against : & & & .